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package org.glassfish.grizzly.asyncqueue;

/**
 * Class encapsulates asynchronous queue implementation:
 * {@link AsyncQueueReader}, {@link AsyncQueueWriter}.
 * 
 * @author Alexey Stashok
 */
public interface AsyncQueueIO<L> {
    /**
     * Get {@link AsyncQueueReader} implementation.
     * 
     * @return {@link AsyncQueueReader} implementation.
     */
    AsyncQueueReader<L> getReader();

    /**
     * Get {@link AsyncQueueWriter} implementation.
     *
     * @return {@link AsyncQueueWriter} implementation.
     */
    AsyncQueueWriter<L> getWriter();
    
    class Factory {
        public static <L> AsyncQueueIO<L> createImmutable(
                final AsyncQueueReader<L> reader, final AsyncQueueWriter<L> writer) {
            return new ImmutableAsyncQueueIO<L>(reader, writer);
        }
        
        public static <L> MutableAsyncQueueIO<L> createMutable(
                final AsyncQueueReader<L> reader, final AsyncQueueWriter<L> writer) {
            return new MutableAsyncQueueIO<L>(reader, writer);
        }
    }
    
    final class ImmutableAsyncQueueIO<L> implements AsyncQueueIO<L> {

        private final AsyncQueueReader<L> reader;
        private final AsyncQueueWriter<L> writer;

        private ImmutableAsyncQueueIO(final AsyncQueueReader<L> reader, final AsyncQueueWriter<L> writer) {
            this.reader = reader;
            this.writer = writer;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public AsyncQueueReader<L> getReader() {
            return reader;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public AsyncQueueWriter<L> getWriter() {
            return writer;
        }
    }
    
    final class MutableAsyncQueueIO<L> implements AsyncQueueIO<L> {

        private volatile AsyncQueueReader<L> reader;
        private volatile AsyncQueueWriter<L> writer;

        private MutableAsyncQueueIO(final AsyncQueueReader<L> reader,
                final AsyncQueueWriter<L> writer) {
            this.reader = reader;
            this.writer = writer;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public AsyncQueueReader<L> getReader() {
            return reader;
        }

        public void setReader(AsyncQueueReader<L> reader) {
            this.reader = reader;
        }
        
        /**
         * {@inheritDoc}
         */
        @Override
        public AsyncQueueWriter<L> getWriter() {
            return writer;
        }
        
        public void setWriter(AsyncQueueWriter<L> writer) {
            this.writer = writer;
        }               
    }    
    
}
